How to Repair the Height Adjustment on your Herman Miller Aeron Chair

Has the height adjustment broken on your Aeron chair? You'll know if it has if it no longer goes up and down & most likely, it will have dropped to it's lowest setting.

If so, it's easy and inexpensive to fix. Read on to find out how.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Replacement cylinder (I'll tell you where you can find one)
• Mallet
• Screwdriver
• Pipe Wrench

1. First, you need to determine whether the height cylinder is broken, or the cable that actuates the cylinder.
   
   Look carefully at the lever, do you see the metal cable?
   
   Then, remove the cover at the base of the chair and push the lever. Do you see the cable moving the part under the base? If so, the cable is not broken and read on. If not, then you need to replace the cable which is not covered in this article.

2. 
   The sticker at the bottom of your Aeron chair.

   Determine whether you need a 1 stage or 2 stage replacement cylinder.
   
   Look at the sticker under the seat of your chair. Your sticker should let you know which one fits your chair. AE1(2)3 or AE1(1)3 the second number is the key, if it's a 2, then you need a 2 stage cylinder. If it's a 1 than you need a one stage cylinder.

3. 
   The Chair Parts Shop

   Where do I find a replacement cylinder?
   
   ...I hear you ask. Well, I have found a few good, cheap, sources. The first, eBay. Often, there are sellers selling both 1 and 2 stage replacement cylinder.
   
   Second, there is an online shop selling replacement cylinders for just $30 + $8 Shipping. They are called Crandall Office Furniture.
   
   Finally, if all else fails, you can get a replacement directly from Herman Miller, but you will probably pay a premium.

4. Now that you have your replacement cylinder, here's how to install it.
   
   First, turn the chair over and use a screwdriver or pliers to remove the retaining clip at the center of the star base.

5. Second, with the star base removed, twist the base of the old cylinder with the pipe wrench.
   
   It will require some significant force to break the old cylinder free.

6. Now, press the new cylinder in the slot left by the old one. Use a rubber mallet to secure the cylinder to the bottom of the chair.

7. Finally, reattach the star base.
   
   There are two different ways that they attach. If it requires a lock clip, the black outer cover of the gas cylinder will need to be removed.

Tips & Warnings

• Find the right cylinder to replace - you will need either a 1 or 2 stage cylinder replacement.
• Be careful when you're hammering the new cylinder in, it requires some force.
• Do not use a 2 stage cylinder to replace a 1 stage cylinder it will not fit.